CODEWITHSUNDEEP
cassandraspark-cassandra-connectorcassandra-2.1
Maniratnam
Maniratnam

Reputation: 13

Is metadata is stored in every node of Cassandra cluster?

In a Cassandra cluster, Let suppose Cassandra cluster have Node A, B and C. Then will Node A have all the metadata information of Node B & C also? and vice versa?

Will we have any separate node which possesses the metadata information of all the other Nodes?

Upvotes: 1

Views: 1098

Answers (1)

Chris Lohfink
Chris Lohfink

Reputation: 16400

The system (and system_schema in recent versions) keyspace[s] holds the metadata on each node that they keep in sync with a different mechanism. If you look at the schema for those keyspaces:

# describe keyspace system;

CREATE KEYSPACE system WITH replication = {'class': 'LocalStrategy'}  AND durable_writes = true;

You can see the LocalStrategy replication strategy which means that mutations to it are not distributed but just applied on the local node. Gossip is used for identifying if nodes have out of date schemas and kicking off updates.

All the data not related to schemas, and which nodes own what tokens are all really only relevant to that node and not distributed in any way. For example compactions_in_progress are just for that nodes compactions. Other nodes compactions or the state of its sstables are irrelevant to other nodes.

Upvotes: 4

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